Event

Abstract

Bacterial spores are encased in thick protein coat, which we have partially reconstructed around bacteria-sized silica beads to create artificial spore-like particles termed “SSHELs”.  SSHELs may be modified with targeting moieties to deliver chemotherapeutics to ovarian tumors in a murine xenograft model. SSHEL-delivered chemotherapy was more effective than the leading liposome-based delivery vehicle in reducing tumor burden while increasing survival. Moreover, SHELL-mediated drug delivery reduced overall toxicity of the drug, which permitted higher localized concentration of the drug at the tumor site. More recently, we have investigated the utility of SSHELs in delivering peptide vaccines. Delivery of a model peptide using SSHELs, in the absence of any added adjuvants, resulted in cross-presentation of the peptide by dendritic cells that produced robust antigen-specific T cell activation. In a murine syngeneic melanoma model, immunization with the model peptide reduced tumor burden and increased survival compared to immunization with the peptide alone. We therefore propose that SSHELs represent a versatile display platform for the site-specific delivery of small molecules and vaccines.

Bio

Kumaran Ramamurthi received his Ph.D. in Molecular Biology from the University of California, Los Angeles (UCLA), where he studied the secretion of bacterial virulence proteins. After a brief research fellowship at the University of Chicago, he studied subcellular protein localization as a Ruth L. Kirchstein National Research Service Award Postdoctoral Fellow at Harvard University. He arrived at the NIH in 2009 as a Tenure Track Investigator, was promoted to Senior Investigator in 2016, then Deputy Chief of the Laboratory of Molecular Biology in 2020. He served on the Editorial Board of The Journal of Biological Chemistry for ten years and currently is an Editor at eLife and Microbiology and Molecular Biology Reviews. He received the National Cancer Institute Director’s Award in 2016 and was elected to the American Academy of Microbiology in 2025. His laboratory studies the fundamental biology of how bacteria divide and differentiate, mainly in the model organism Bacillus subtilis and the pathogen Staphylococcus aureus. On the applied science side, his laboratory has developed “SSHEL” particles, inspired by bacterial spores, as a vaccine delivery platform and to deliver chemotherapeutics to solid tumors.